In Saijo U.S. Pat. No. 3,788,374 a parenteral solution bag is shown having access ports which are closed with a tear seal, openable by manipulation of a rearwardly extending tear tab. The tear seal comprises a tube passing through a peripheral seal used to join a pair of flexible plastic sheets together into a bag, with the tube carrying a diaphragm across its bore at a position intermediate of the ends of the tube. An outer seal about the tube comprises a closed envelope with a tear tab, for tearing open the envelope.
The container of the above-cited Saijo patent may be manufactured by inserting a mandrel through an open rear end of the unsealed bag, and into the inner portion of the tube which is sealed across the peripheral seal line of the bag, so that the sealing operation does not collapse the tube, the mandrel providing a source of rigid resistance. The mandrel of course cannot advance outwardly through the tube any farther than the diaphragm which occludes the bore of the tube.
After the sealing step, the mandrel is withdrawn from the inner end of the tube and the inside of the bag, and the end of the bag is sealed.
The above manufacturing process is cumbersome, since it is clearly inconvenient to have to open up the end of a pair of thin plastic sheets to insert a mandrel through the entire length of the bag.
In the invention of this application, the sealing mandrel can enter the flow tube which crosses the sealed periphery of the bag from the outside of the bag, providing very substantial manufacturing convenience, and avoiding the need for the mandrel to pass the entire length of the interior of the plastic sheets which are sealed together to form the bag.
Furthermore, the simpler outward approach of the mandrel opens the opportunity for automated assembly of the closure system of this invention, providing potentially great cost savings.
Also, other design advantages of the bag of this invention are provided over the containers of the known prior art and particularly that of the cited Saijo patent, and also U.S. Pat. No. 3,343,541, specifically, for example, by the fact that in the sterile openable seal of this invention, the inner portions of the outer seal, upon opening, surround the sterile outer end of the flow tube more uniformly, for added assurance that contamination of the sterile outer portion of the tube will be prevented.